how to help DD?

No! Just say no.
The 16 year old can have the baby in with her. Tiny babies actually cost very little unless you insist on everything new. It will be months before space becomes an issue (and it may well stay fine anyway). They are lucky to have 5 bedrooms. Most people don't have space for a nursery at all.

I think your daughter is in shock and will feel better soon.

This really isn't your problem to solve. I understand you love your family and want to help, but you have been a mother and grandmother and your life and home must now surely be yours to enjoy and live how you choose. This has been a shock for all of you, but the baby has a father whose family should be involved too. Just because you are in a better financial position does not mean you have to pay for anything regarding the baby. It's not your responsibility.
What about SIL's family? She is their GC too. Say No and stand back; you can support later if needed. I am sure that after a short time other solutions will become available.

I wouldn't take on the responsibility of the mother and child. You will be stuck with it for years. Time for the girl to "grow up" and, if she wants to keep the baby, work out a plan. No use relying on other people to clear up the mess you have made. Harsh but true. Good life lesson.

I don't think you should accept responsiblity for your pregnant granddaughter.

In your place I would invite the girl for a chat, outside if she is not part of your bubble and ask her:

what part the father of the expected bairn plays in all this?

how she intends to support herself and her child?

Offer to contact Citizens's advice with her or for her to ask about social security, maternity benifits, housing etc. for her.

Tell her as kindly as possible that if she wants to keep the baby, she needs to start planning realistically how she is going to support it and herself.

I would also volunteer to talk to the putative father, as no-one else seems to be holding him responsible.

I hope you can get something in place for her. Plenty of women have had a child at her age. It is not what we want to see happen to a girl, but it can turn out well, if she gets the help she needs .

However, continuing to treat her as a dependant child is not the best or kindest thing in these circumstances.

Lots of good advice on here and I was just about to wade in and add my mite but it looks like the OP has left the building.
She has, presumably, made a decision by now.

My niece had a baby while still in the sixth form. My sister cared for him while she was at school, but she had to look after baby after she came home from school. She got into university and studied pharmacy, the baby went to the university creche. Later on she married a lovely man and has two more children.

I've had a quick google and found this;

healthforunder5s.co.uk/sections/pregnancy/help-for-young-parents/

It looks like it might be useful? I only know what is local to me but there are various local charities and organisations who will be able to help and the local authority will fund schemes aimed at teenage parents too.

The dust will settle soon x

Maybe it's me. but why does this new baby need its own room ? No reason why, at least to start off it can't share the parent's room!
I assume that the 16 year old has her own room? Her baby can share with her and in fact she may find it easier.
DD and GD can look on Marketplace or their community FB pages for baby equipment for them both - often there is things being given away.
In some ways it will be nice that DD and GD can share their pregnancies and birth and have the two littlies grow up together.
A bit later on, it may be possible to find out what support and also housing is available for the GD. Many councils have flats/ small houses available for single parents .

Is the husband/father, the biological father of ALL of the children?

Yes, that is very true MOnica. And that is of course, supposing the OP actually wants to invite someone else into her home.

My situation was v different, because my DD was an adult when my miracle GS occurred. But I had them to live with me. Which didn't work for DD and I, but definitely DID work for DD, GS & I. A nightmare at times, because... babies / young children are very hard work. But also babies and young children are wonderful.

I wouldn't change a thing about it. BUT I am not the OP and her DGD is a child. Much harder.

GagaJo The one thing that would make me nervous about your eminently practical suggestion, is that the teenager will see themselves as being pushed out of the family home, because of the behaviour of another and is therefore expendable.

I write these words of caution because I have twice seen something similar in friend's famiies . In each case the father remarried after being widowed, and, as the wives were in their 40s, they didn't think they would have children, but they did and as a result two older children, in their early 20s were asked to move out. In each case this led to difficulties and estrangement in the family as the older children felt they were driven out of the family home by their father.

Just a word of caution. This arrangment could have the same effect.

I agree with GagaJo, your daughter is panicking and projecting it onto you as you are her Mum and Mum's know what to do. I would try to keep out of it as much as possible until you are forced to say no (which is completely understandable)

Is your Granddaughter still at school? I imagine once the school know it will be flagged up and the school may know more about local offers of support etc

But as others have said, your DD is currently panicking. Nothing specific needs to be decided now.

Possibly contacting social services now would be a way to start support, before your DD is heavily pregnant.

If you WANT to help (and if you don't, you really shouldn't have to, it was your daughter's choice to have such a big family) you could offer to have the other teenager to live with you.

Mind you, a teenager is not easy either, but a lot less work than a teenager with a baby. The other teenager might welcome getting away from the family chaos. Alternatively, you could just have the younger two to stay a bit more often.

The pregnant teen will have to have her baby living with her, in her bedroom. And maybe once she is 18, her parents could help find her somewhere of her own to live. Her child will be just over a year old then, and she will be able to claim Universal Credit.

I would have thought that the whole family now need a social worker. That would work in their favour, because the social worker will be able to support applications for benefits and possibly for social housing for the pregnant girl.

I don't understand the comments about furniture? New babies don't need much, plus there will be another baby there as well so what's the issue? There are fantastic second hand cots, buggies etc., and your GD will just have to 'man up' and buy what she wants, your family should not expect you to be doing this. The proposal is very unfair, you will likely be cast as the villain here, but none of this is of your making. As others have said, your GD has her own room, they have a 5 bedroomed house and many families have to cope with less. Your DD is possibly panicking at the thought of two babies, a grandchild at the same time as a child, and probably can see herself raising two babies, not one as she planned. Help with baby sitting, provide a peaceful refuge for visits from those who need it, but don't be emotionally blackmailed by your family.

Five bedrooms is much bigger than many much larger families cope with. Are there any rooms downstairs, that could be turned into a bedroom? If the 16 year old thinks they want to keep the baby themselves, then they also need to be included in discussions as to how that is going to work. Not expect other people to sort it out for her.

Is she going back to school after baby is born? Who is going to look after baby,. Seems as if that child will have an uncle or aunt of nearly the same age. So, could they be taken through those first two or three years together?

When my children were younger we had a five bedroom house (had divided one large room to make two), and it did mean most shared rooms. We managed eight (we fostered in those bedrooms, and turned a room in the ground floor into a bedroom for ourselves.

It is hard enough for parents to take on the responsibility of a g.child from a young teenager, let alone a g.parent to take on this responsibilty.

If your granddaughter is one of the teenagers who has her own room, then she should be able to manage to squeeze a cot in, many families live in cramped conditions. You could possibly offer to buy the essential baby equipment such as a cot, pushchair etc but some items could be shared with your daughters new baby.

Adoption of the baby ?

I wonder if perhaps, and I’m guessing their isn’t a lot of spare money, to go on the girl speaking to a therapist on her and own with the family to work out her choice with the pros and cons?

It may seem like a good choice now but will set her up for a life time of hard work and hard choices. I had a pregnancy scare just before I married DH and was planning to have an abortion as I wasn’t emotionally or financially read for a baby ( having taken on a mortgage that required my wage for our bills and sundries). I’m glad I waited, motherhood for me was at the right time when I had more support and financial stability.

Don’t take on the responsibility, perhaps if your house and financial support is taken out of the equation having a baby might seem less of option.

I know what I’m saying won’t be popular with some, but I think abortion is (pardon my words) a godsend.

I’d say no, as others have said this is a huge responsibility. Quite rightly this is your time to make plans and enjoy your life whilst you’re fit and able to do so. I’d be quite firm, you don’t have to justify your answer, do it soon before assumptions are made. I also think they need someone in the family, not you, to have a good chat about contraception.

Do not agree to this proposal; you will be lumbered with this irresponsible girl and her child for years to come. A friend is still supporting her sixteen year old daughter and twins twenty years on; none of the three work.
Your daughter and her daughter must sort this out.
Some possibilities occur to me , if, and only if, you wish to help.
Could the oldest teenager lodge with you, to free up a room?
Could you offer to help financially, contributing towards rent, baby items, child care?

I suggest this only because I feel pressure will be applied by these feckless parents to make you feel guilty.
A horrible situation, and not of your making.

In our neighbourhood there are people who foster teenagers and their babies. at least I know one who used to do this and she taught the girls how to look after their babies, and how to manage. I used to babysit for them as they had 4 DC of their own while the young mum dropped into the kitchen to heat a bottle and make a cup of tea.
My df was teaching the girl to knit. I know the girls were so appreciative and kept in touch long after they were settled in a flat.

However your DGD has a partner too, I guess. Does he have any visible means of support?

I know the family may think it harsh that you are not rushing to help but I am sure they will understand if you can't. Why not have a talk to your DGD? A proper family discussion is called for.

As the DGD has a room of her own already, I am puzzled as to why she might need to come and stay with you. Or maybe I have not understood this properly.

You cannot take on a teenage Mum and new baby; but you could maybe offer other sports of support - e.g. occasional babysitting.

You love your daughter, son-in-law and their children. This is THEIR child/grandchild, not yours. You have been there , done that. This is YOUR time, your post makes in clear you don’t want to do this and neither would I – neither would a lot of other folk on Gransnet. Be strong and definite when you reply to your daughter... pretty sure the 16 year old has no clue what having a baby entails, as we know the pregnancy really is just the beginning. It is every minute of every hour of every day for the rest of her life that will be changed forever. And that it for her parents and her to sort out. It would be very convenient for offload all this hassle on you. And also utterly unfair.

It is selfish of your daughter to put you in such position.

You have the right to say no and not to feel guilty

Your dd and her family will have to think of a way to make it work